Isolation-free Identification and Phenotyping of First-Trimester Extravillous Trophoblasts Recovered from Cervical Fluid

Document Type

Conference Proceeding

Publication Date

11-2025

Publication Title

Placenta

Abstract

Objectives: Placental malplacentation underlies pregnancy disorders such as pre-eclampsia (PE) and fetal growth restriction (FGR), yet current blood-based screening assays perform optimally only in mid-gestation. Direct interrogation of placental cells during the first trimester could transform risk stratification, but existing trophoblast retrieval and isolation from the cervix (TRIC) is technically demanding. We therefore developed an isolation-free, swab-based workflow coupled to mass cytometry to sensitively identify and characterize extravillous trophoblasts (EVTs) in first-trimester cervical fluid.

Methods: Endocervical specimens (9– 14 weeks gestation) were collected with flocked swabs, shipped and stored under defined conditions, and processed without enrichment. Samples were bar-coded with palladium, spiked with metallotope-labeled reference cell lines, and stained with a Cytometry by Time of Flight (CyTOF) panel targeting HLAG, CK7, PAPPA, CD45, and HLA-ABC, among others. Signal drift was corrected by dual normalization to EQ™ beads and reference-cell intensities. EVT gates were defined as HLAG+ CD45– CK7+. Stability of cell recovery and antigen expression was assessed after shipping and–80 °C storage.

Results: HLAG+ CD45– CK7+ EVTs were reproducibly detected in every sample (n=22). PAPPA was highly expressed within this gate, confirming placental origin, whereas maternal cells lacked these proteins. Cell yield, viability, and biomarker intensity were unchanged after shipping or frozen storage. Preliminary analyses indicated significantly different biomarker expression profiles in EVTs from pregnancies later diagnosed with PE/FGR, relative to uncomplicated controls.

Conclusion: We present the first isolation-free protocol for quantitative phenotyping of cervical EVTs in early pregnancy. The platform is robust to routine clinical logistics and reveals altered protein expression profiles in pregnancies destined for malplacentation. Integration of this assay into first-trimester care could enable earlier, biology-based prediction of PE and FGR.

Volume

171

First Page

e250

Comments

Congress of the International Federation of Placenta Associations, September 17–20, 2025, Erfurt, Germany

Last Page

e250

DOI

10.1016/j.placenta.2025.08.069

ISSN

0143-4004

Link to Full Text

Share

COinS